lec 19 Flashcards
rivers and streams are turbulent. what is one key difference between them and lakes?
whole lotta interaction bw water and sediment
what is the riparian zone?
technically terre attached to a aq environ - can be thought of as “transition zones”
an area surrounded by vegetation (lots of input + interaction – ‘hotspot for nutrient cycling’)
as we move from headwater into higher order rivers, how do rip zones change?
in lower order headwaters, organic soils in water is elevated due to overhanging vegetation
in larger rivers, lots of channel migration and movement across floodplain
what is the diff bw buffer strip and rip zone?
buffer strip is a management tool is vegetation left beside catchment, largely for harvesting
rip zones are heterogeneous over time and space. what do we mean by this?
over diff times (seasonally) water levels vary.
what is “patchy soil”
flood processes create patchy soils where waterlogging facilitates anoxia. patchiness refers to areas of life, nutrients, etc
what effect do riparian zones have on water flow and sediment deposition? what is sediment deposition largely dependent on?
riparian zones tend to slow waterflow - if rip zone overlaps w vegetation, this slow is even greater
slower the waterflow, the greater the amount of sediments is deposited
“size dependent effect”, the size being the size of the body of water
what is erosion velocity? what is fall velocity?
velocity required to pick up sediments assoc w substratum (sediments usually experience adhesion making them not free floating - velocity is needed to take it out)
conversely, fall velocity is the speed at which sediment of a certain size falls out of water and into substratum
(ie how fast water needs to move to pick something up vs how slow it needs to move to drop something back into sediment)
what are some problems assoc w free floating sediments?
- clog fish gills
- clouded water affects prim prod of algae and plants
lateral mvmt from unsat soil (upstream) to saturated soil downstream. what does this convergence entail?
lots of biological activity in downstream catchment
downstreamsoils are usually anoxic, which can provide space for nutrient trapping, chem reactions/bact mediated reactions, and in general how organisms uptake nutrients
what are the conditions for denitrification
- supply of NO3
- lack of O2
- lots of carbon substrate to work on
boyne river north of toronto, studies were done that found what relationship bw nitrate and distance over time?
catchment further away from the river has higher nitrates; as u get closer to the river, nitrate conc greatly decr. this is bc as u get closer, bacteria had more opportunity to undergo denitrification
also chloride was used to track the parcel of water to make sure no funny business was going on >:(
